US2664923A - Machine for splitting or resawing insulating boards - Google Patents

Description

Jan. 5, 1954 E. R. FERRARI 2,664,923

MACHINE FOR SPLITTING OR RESAWING INSULATING BOARDS Original Filed Nov. 16, 1951 4 Sheets-Sheet 1 l|fiIil1r- -19 Da'lum Plane J "K Wark 197d I 1 e 5 Y Pan i "J INVENTOR. .Er'n es? R.Ferr'a r1 Jan. 5, 1954 E. R. FERRARI 2,664,923

MACHINE FOR SPLITTING OR RESAWING INSULATING BOARDS Original Filed Nov. 16, 1951 4 Sheets-Sheet 2 N m m r w m Is E LH IN VEN TOR.

Ern e sl' P. Ferrari Jan. 5, 1954 E. R. FERRARI 2,654,923

MACHINE FOR SPLITTING 0R RESAWING INSULATING BOARDS Original Filed Nov. 16, 1951 4 Sheets-Sheet 3 IN VEN TOR.

frnesi'R.F rrari w L7H Patented Jan. 5, 1 954 MACHINE FOR SPLITTING OR RESAWING INSULATING BOARDS Ernest R. Ferrari, Vancouver, Wash., assignor to A. W. Schaupp and E. R. Ferrari, a copartnership, doing business as American Smooth Saw 00., Klamath Falls, Oreg.

Original application November 16, 1951, Serial No.

Divided and this application October 14, 1952, Serial No. 314,663

3 Claims.

My invention relates to the splitting or resawing of insulated board edgewise to provide cut pieces or sections which maybe used in the production of simulated split shakes and siding. To this end, the cut pieces or sections should be ta pered so as closely to resemble a tapered wood shake or siding. It is difficult, if not impossible, economically, to form insulating board originally in tapered sections. Accordingly, many efforts have been made to resaw or to split the sheets edgewiseon a taper to produce two complementary wedge-shaped pieces. These eiforts, however, have failed or proved impractical. The difficulty involved is that the sheets of insulating board are quite thin, spongy, soft, and fragile so a splitting or resawing operation cannot be per formed economically and efficiently by conventional methods or with conventional machinery. I use the word resaw herein to connote sawing edgewise of a sheet, not flatwise or crosswise and without relation to the fact that the sheet is originally laid or formed without a sawing operation.

;- =Insul,ating board is formed from a web of matted fiber in a manner similar to the one by which paper is made. Because of the fact that the web is made by flowing or otherwise applying a wetted sheet of material to a perforate surface, it is difficult, if not impossible to lay such a sheet with a varied thickness or a tapered section. Efforts made to split sheets of insulating board edgewise heretofore have been unsuccessful because of the fibrous, spongy nature of the material and the soft, fragile texture of the finished board. For example, a resaw of usual construe I tion will tear and rip the fibers of the board and will produce an uneven cut surface. Furthermore, to form a simulated shake from a board of standard size, it is necessary to sever the thin tions are produced. Another and greater difficulty and hazard is that conventional efforts to split edgewise or to resaw sheets of insulating board pull out small pieces of material which pile up and wedge about the clearance space for the saw blade or other cutter which is forming the split or kerf, and these pieces produce friction 2 and generate heat to such an extent that ignition of the highly flammable material results. Because of this fire danger, the resaw of an insulating board has become known in the industry as an ultra-hazardous undertaking.

I have discovered that sheets of softinsulating board may be split edgewise by the use of a so-called smooth saw bandsaw if ordinary resawing procedures are modified in several respects withregard to (1) guiding the sheets into the sawing area, (2) holding them to a fixed plane and pathway, (3) compressing'the sheets being rived by this sawing action over the area where the sawing is being produced and rearwardly thereof, (4) flooding or wetting the sides of the saw blade with a liquid, such as a solvent, to prevent the binder in the insulating board from accumulating on the blade, and (5) inclining the sheets obliquely to the plane of the saw blade so the usual supports and operating mechanism provided for the saw may be utilized.

My invention is embodied in a new machine which makes practical and safe the performance of such edgewise splitting or resawing of sheets of insulating material.

That material which generically is termed insulating board and with which my invention is concerned is produced from a variety of source materials. These source materials, in the main, involve the utilization of waste products, such, for example, as the stocks of sugar cane, corn stocks, flax shives, straw and wood chips. My experimental work has been done in the main with insulating board made from wood chips of Douglas fir and a bitumen binder. One type of insulating board of this latter character is sold under the trade nameof Firtex. However, this trade name material is but one exemplary type of insulating board and my invention is intended for use with insulating board generally.

One common attribute of all insulating board is that it is soft and spongy and has little tensile strength as compared with hard board. some insulating board is produced in sheets having relatively smooth, dense surfaces, from a fibrous mass having incorporated therein a resinous or bitumen binder. Some of these binders are quite flammable and most insulating boards exude the binder materials in the presence of heat such as is produced ina resawingaction. This exudation, then, is a problem since it tends to form a hard deposit upon the saw blade and, after a short period, the deposit builds up to such an accumulation that it renders the saw blade ineffective for producing a clean cut. Thereafter, either the blade must be removed or the machine must be stopped so the blade can be cleaned. I have discovered that the formation of these deposits and accumulations can be inhibited or prevented entirely by maintaining a wetted surface over the faces of the saw blade as with a liquid solvent or cleaner applied in such volume that it will .be taken up by the sawdust produced in the sawing action. This sawdust continuously will wipe :the solvent away and will carry with it any accumulation of binder which is exuded from the sheet under the heat produced by the resawing action.

My experiments in connection with this subject have established that the resawing or edgewise splitting of insulating board successfully may be produced with a saw tooth .of the type disclosed in the United States patent to Ferrari and Hoffman, No. 2,071,618. In the sawing art, this type of tooth is used to produce --s-mooth sawing. It differs from the ordinary tooth in that the points are more narrow than the base and the sides diverge from the points toward the gullet. Further, the divergent tooth sides are maintained quite sharp so as to plane or shave the walls of the saw kerf to a degree that boards thus sawed resemble planed boards rather than sawed boards.

I have discovered, however, that the use of the above described type of saw tooth alone or per se will not be satisfactory to resaw or to split sheets of insulating board edgewise. The difficulty arises due to the fact that insulating board is quite spongy and it tends to yield under pressure so the divergent sides of the teeth cannot perform their intended function as they do in lumber. This might be likened to the act of a man shaving his whiskers. The whiskers cannot be cut off sharply and cleanly unless some substantial pressure be applied to the skin either by pulling the skin taut or by pressing the razor tightly against the skin. I have discovered that the same effect and result can be obtained in sawing by mounting two flat shoes closely adjacent the sawing area, which shoes are arranged to engage the opposite faces of the insulating board and to hold the board tightly against the saw. These shoes must be relieved somewhat over the area where the teeth rout out the bottom of the kerf so the saw does not become pinched. They can exert substantial pressure, however, over the gullet of the saw blade and this pressure causes the two halves of the split sheet to be bent inwardly and to rub against the gauge of the saw. Such a slight rub is sufficient to hold the surfaces of the kerf against the saw blade and to produce the shaving or planing action which is so important.

A second and equally important result is produced by the use of these pressure shoes at the sawing area. Thus, the wedge-shaped sections or simulated shakes which are to be produced must narrow to a thin edge, approximately oneeighth of an inch thick. The boards are resawed or are split on edge, however, and the cutter or saw blade moves toward the saw table in passing through the cutting area. Thus, the board is supported by only one thin edge, which edge bears against and rests upon the saw table and lower guide while spanning the tooth clearance opening. It is the fast moving ripping action of the moving saw blade which tends to pull upon 4 this thin edge of the board and of the cut pieces sufliciently to break chunks therefrom. However, in accord with my invention, if the sides of the board and the cut pieces are held tightly by the shoes and a substantial pressure is exerted thereby, the soles will prevent the thin edges of the cut pieces from crumbling or rupturing. That is to say, the rubbing pressure of the shoes on the .thin out area tends to hold this critical thin edge integral and unbroken, even though the board and cut pieces have only an edge contact for support. The upper edge of the board, on the other hand, does not require as much support since the saw is moving downwardly away from the upper edge. Thus, the entire body of the underlying board acts as a support and rupturing does not occur so readily. That is, the material itself has sufiicient strength to resist breakage along the upper edge during the sawing operation.

For the above reasons, it is one object of my invention to provide a pair of spring pressed and parallel mounted shoes for a bandsaw machine, such shoes to be positioned on opposite sides of the saw blade where they will contact, hold, and press the cut pieces of board as these out pieces flow past the saw blade. In contrast to mere guides, these shoes press upon, compress, and support the cut pieces effectively to strengthen the same at the critical areas.

Another object of my invention is to hold and press the cut pieces together, with a preselected pressure, as these pieces move past the gullet line and the rear portion of the saw blade.

In conjunction with the smooth saw teeth above mentioned, my invention employs a tunnel which is complementary to the shape of the board which is to be split. This tunnel is unique in that it is bounded by power driven elements which move the board toward the saw and by guides, fences, and idlers, which steer and guide both faces and both edges of the board with precision while it is moved. Additionally, the tunnel is tilted with respect to the saw blade so the board will encounter the teeth at an angle rather than straight on and the cut pieces therefore Will acquire the desired taper .or wedge-shaped appearance to simulate shakes or siding. Sequentially, my invention proceeds by moving a plurality of the boards through the tunnel and past the saw blade, one after another, in a steady stream; by abutting each board end to end as it is moved along; and by supporting and holding the cut pieces together with a preselected pressure as they pass the saw blade. Commercially, this has proved practical and near perfect cuts can be made so long as the insulating board is of the type which employs no binder. If, however, as is common with many insulating boards, a low melting point bitumen or resin binder has been used in forming the board, experience has shown that this binder will present an additional problem. Thus, friction is developed as the splitting or resawing progresses, and this friction heats the saw blade to a temperature where the bitumen or resin binder is exuded. As previously explained, a certain amount of this material will accumulate upon the teeth and upon both faces of the saw blade. For example, if a band resaw blade is utilized, substantial heat is generated adjacent the work area of the blade, yet only a portion of this heat is dissipated adjacent the return area of the continuous saw blade. Accordingly, that binder which is exuded tends to harden and to accumulate as the blade moves along and is cooledl Such an accumulation of binder can be fatal to'the successful practice of my invention. Further, experience has shown that constep wherein the saw blade continuously is flooded, wetted, and bathed with a liquid. This liquid may be a solvent which acts as a vehicle for the binder, it may be lower fraction oil which acts as a coating, or it may be another wetting agent. In any event, the binder must be carried away with the sawdust so a clean 'saw blade is, at all times, maintained.

A further object of my invention is to provide, in combination with a bandsaw machine for splitting a thin sheet of cellulose fiber board, a spray type dispenser means which will bathe both faces of the saw blade with a liquid and which, because of the concentric nozzle structure employed, will do so more efficiently and effectively than those mechanisms heretofore employed.

Yet another object of my invention is to provide a frame member having a flat area defining a datum plane, a continuous bandsaw blade which intercepts said datum plane at right angles adjacent two spaced areas, the first such area to define a saw work plane and the second to define 'a return plane, a work bed which is rotatably adjustable with respect to the bandsaw blade, and a plane work feed tunnel for the boards.

-More particularly, the work bed and plane work feed tunnel above defined are tilted at an angle to the datum plane and the saw work plane, respectively, so the insulating board which is fed through the tunnel will be cut at an inclined angle to produce two tapered pieces which are wedge-shaped.

Another object of my invention is to provide, in combination with a work bed, a plurality of work guides, fences, and power driven feed rolls which are aligned with precision and accuracy in pairs and which are spaced one from another to bound a plane work feed tunnel of the same width and thickness as a board which is to be split or resawed. This tunnel serves to steer and to guide the board in a unique manner since it bounds, bears upon, and engages the top, the bottom, and both faces of the board.

. The above and other objects, capabilities, and

3 being taken substantially on the line 3-3 in Fig. .2, showing the spray type dispenser jmeanswhich floods or bathes the saw blade with a liquid or solvent and showing the two part fabric wiper which is spring. biased to contact jthe faces of the saw blade and spread and in. the liquid or solvent thereover;

" [,Fig. 4 is an enlarged detail view, taken sub ;stantially on the line 44 of Fig. 1, showing two "sheets. of soft insulating board being. moved lalong the feed tunnel which is defined and bounded by a plurality of guides, rolls and Fig. 5 is a perspective view'showing a sheet of "the; insulating board with'the" saw blade in the llt'erffoneof the ressure shoes here being show-nin correct posltion'bearing against the side of the board (the other pressure shoe is not shown in this view); Fig. 6 is a perspective of the saw blade, lower guides, and bed with the board removed;

Figs. 7 and 8 are related enlarged and'somewhat diagrammatic cross-sectional views looking :-down through a kerf as it is cut'by a-co'nventional saw tooth and by a scraping type saw tooth, respectively, Fig; '1 illustrating conventional orprior art, forming no part of applicant-s surfaced, clean kerf produced by the smooth Figs. 9, 10 and 11 are related top, front and back views, respectively, showing one form of the tapered or scraper type tooth with which the method of the instant invention is practiced;

and

' Fig. 12 is an enlarged detail view which is more or less diagrammatic and which is taken in cross section through a sheet of insulating board with the saw in the kerf and with the pressure shoes bearing tightly against the sides of the board so the thin edge will not crumble or break off.

In Fig. 1, I have shown a more or less conventional single blade band resaw machine with which I have embodied the principles and novel elements of my invention. This machine includes a main frame member I I havingthe usual horizontal flat top area defining a datum plane. This datum plane is so labeled in Figure 1. An electric motor I2'is mounted upon the flat topof the frame member and is joined, by a belt I3 and two pulleys M, to the lower or power saw wheel l5. This power wheel I 5 in turn, is mated to an upper or idler saw wheel l6 and a continuous bandsaw blade I! is reeved thereover. Thus, the bandsaw blade I! is power driven to intercept the datum plane at right angles adjacent two spaced areas. The first such area'I define as a saw work "plane (see l8 wherein the blade moves down) "filed November '16, 1951, Serial No. 256,714, the

instant machine may be equipped with the mated inner and outer halves of a bandsaw guide 20. Further, the work bed 2| of the resaw machine rotatably is adjustable, upon a journal bearing Zia; with respectto the aforementioned datum plane. Such rotational adjustment takes place about a journal bearing axis which lies within the datum plane and within the saw work plane 18, the axis being located in a direction perpendicular to the plane of the drawing of Fig. 1. In conjunction with the rotational'adjustment, the work bed carries a massive ear 22 which cooperates with a slotted slide 23 and a. bolt 24 toadjust and to set the angle between the plane of the work bed and the datum plane.

This angle, as indicated in Fig. 1, is a small acute angle for the purposes of the instant invention so that tapered pieces will be cut from a rectangular board.

In comparison of Figs. 1 and 4, the work bed 2| carries a plurality of work guides, fences, and power driven and idler feed rolls which protrudethereabove for adjustment about the or horizontal guide or fence 28.

Journal hearing lla with the work bed. These elements :include four power driven 560(131011515,

slide having a tightening bolt 32 which is adapted to 'grip the complementary upstanding pipe 33. Thus, since the pipe 33 is joined to the work :bed 2|, as by bolts 34, and since the valrious'rolls andthe side fence 2'! also are carried by the work bed 21., rotation of the latter will cause these elements to tilt or rotate the same amount. In

summary, then, the various fences, guides, and

rolls may be said to define a plane work :feed

:tunnel :which is adjustable in sizeand which is best made to conform, a .complemcntary'manner, to the size of the board which .is-to .besawed.

The rolls and side fences grip thgtwo sides of .a

board, the top fence slidably guides the top of the board, and the work bed guides the bottom thereof. Further, because the various adjustments are provided,-the boundaries "ofthe tunnel canbe set to a small fraction of an inch. Such accuracy is important to my .invention.

In '4, another important feature of my invention isshown. Thus, there is shown a pair at insulating boards in the-process of being fed,

by the hands of a saw-yer, through the aforementioned feed tunnel and againstthe vbandsaw blade 11. These boards, in accord with an important factor in this invention, arean insulating boardwhich, because of-its:soft,-spongy and weak nature, is very difficult to split. Both of 'the boards are identified b the numeral 35 and, as they now through the work tunnel, the various guides and fences bear upon the top, the bottom and both faces thereof. Furthermore, as the boards actually are being sawed by the blade 41, a pairof flat pressure vshoes 36 bear upon and support the outer surfaces of the board and the cut pieces with a compressive force. This compressive force is generated by an adjustable compression-spring 31 which is held intermediate one .of the pressure .shoes and the secondary "frame member supporting the shoe. The spring force is adjusted by a threaded nut system 31a. As best shown in Figs. 4 and 12, each of :the flat shoes 36 has a tapered end 36a so, in effect, .a funnel is formed. Further, the entire shoe extends upwardly to a point closely adjacent the top of the board and it extends -.rearwardly subtsantially the width of the saw blade. Thus, the out pieces of the boards 35 are pressed tightly together as they pass over the saw blade. By this pressing action, the-shoes 36 serve two separate functions. Firstly, they support the cut pieces to prevent crumbing and, secondly, they amplify and support the shaving and planing action of the saw teeth as hereinafter will be explained with reference to Figs. .9, 10 .and 11. .In use, these functions areevidencedrby a slight lateral movement of the nut system 3-1 aeach time a board passes between the shoes .315. Thus, the pressure shoes 36 form an important part of my invention.

Further to illustrate the structureand function of the pressure shoes 36, I have provided the mlarged diagrammatic view of 12. In this figure; the arrows :F indicate :the direction in which the board 35 is fed against and past the saw blade H and the arrows P indicate the direction in which the pressure shoes 36 exert a force against the sides of the board. By way of :example, -I have found that a total force (P) of about :10 pounds is sufficient to support a :of Firtex insulating board which is one half inch thick, 16 inches high and four feet long. Thus, the board-itself is quite p ngy and yieldable in contrast to lumber or hardboard. Consequently,

teeth of the saw blade are attempting to :rip

and to plane a material which gives, under pressure, much as a piece of cardboard would give. I counteract this give by supporting the 'board withthe pressure shoes. On the other hand, the shoes 36 cannot press inwardly at a point opposite the saw teeth or the saw will bind and overheat. This danger points up another reason for forming the'shoes 36 with the tapered, :cut-

away portion 360.. In short, the shoes must be provided to support the cut pieces rearwardly of the gullet line and along the sides of the so the sawing can proceed, but they also must be relieved or tapered opposite the teeth so the sawing can continue.

Yet another function is served by the pressure shoes 36. Thus, as is well known in the sawing art, thatportion of the bed of the resaw machine which is located directly below the tooth and gullet structure shown in Fig. 12 is relievedor cutaway to provide an opening (-54, Fig. -6) through which the blade and the teeth maypass. -.Consequently, a majority of that portion of the board which is shown in Fig. 12 is unsupported from beneath. However, this same portion is the-most critical area in the entire weak, spongy board. This is for the reason that the blade If! is moving down through the unsupported area and the teeth are pulling upon and ripping the kerf over this area. With conventional methods of sawing, this pull will break off and crumble the thin lower edge of the board and imperfect pieces will result. In practice, a lateral support pressure is exerted against the sides of the board. This support may be provided by the pressure shoes 36 or by an equivalent structure. In any .event, by holding the cut pieces together against the saw blade directly behind the teeth, asupport is provided to counteract a certain amount of the tooth pull. This support, then, is in addition to that support which resists the lateral -give.of the spongy materialand it is an important part of my invention.

Returning now to a comparison of Fig. '1 with Figs. 2 and 3. the latter are enlarged detail views of thespray type dispenser means 38 which is mounted in the return plane 13 of the saw blade. Thus, .a long horizontal mounting rod '39 protrudes from and is carried by an upstanding rear portion .of the main frame member ll. Four separate clamps encircle and grip this rod 33. Asshown in Fig. 2,1two of these clamps carry the mated concentric nozzle structure 40, whereas .two more carry the complementary halves of a fabric wiper 4|. The nozzles .40 are aimed or directed at the front .of the saw blade ll against the .gullet line of the teeth. The fabric wipers Al, on the other hand, contact the entire lateral area of the saw faces. Thus, each nozzle in- .cludesaliquid supply hose [2 and an air supply hose 43. As indicated in Fig. 3, air'under pressure is emitted from the outermost or annular nozzle, whereas liquid, such as the aforementioned solvent or .oil, .is emitted from the central or circular nozzle. In effect, this provides an atomizer action which breaks up the small drops of liquid to form a fine mist or spray as indicated diagrammatically at 44. Further, as shown in Fig. 3, this spray 44 contacts the saw faces just below the two fabric wipers 4|. Since the wipers 4| are spring biased into contact with the saw faces, as with a spring 45, the fabric soon becomes wet or impregnated with the liquid and the entire lateral area of the blade is wiped, flooded or bathed with a uniform coating of the liquid. By way of example, if the binder in the board is a bitumen, the liquid should be a solvent which is a lighter fraction of the same source material. On the other hand, I have tried water as a wetting liquid. In any event, the wetting agent should wet or flood the sides of the blade completely so a coating is provided. If this coating isthorough and complete, the binder material which is exuded from the board will not stick to the blade. Instead, the binder will be wiped off by the sawdust during the sawing operation. Further, a certain amount of the liquid also will be wiped off and it is for this reason that an efficient spray type dispenser should be used.

- Turning now to Figs. 9, and 11, I have shown a typical shaving or planing tooth which is capable of producing the smooth saw results previously described. This particular form of the tooth is made with a relatively flat face 46, a straight top 41, and with divergent planing edges 48. In function, the straight top edge 41 of the tooth serves initially to rent out a narrow kerf in a board and the divergent edges 48 Widen the kerf to it'seventual width by planing and dressing the walls defining the kerf. The taper whichproduces the divergent edges may vary from zero; to ,005 inch or more, depending upon the action desired. I v

This function of a shaving type tooth best is'illustrated in Fig.3 where a cross section of the tooth is shown as it forms a kerf in a soft cellulose fiber insulating board 49. Thus, the narrow straight top 41 of the face 46 is routing out the floor of a kerf through the board and the divergent edges 48 are planing, shaving, and dressing the walls defining the kerf. In Fig. '7, on the other hand, a conventional saw tooth 50 isforming a kerf in a similar soft fiber board 49. In this latter figure, the tooth edges 5| are ripping and tearing out the fibers. Because the conventional tooth 50 has no shaving, or planing action, the sides of the kerf are not smooth as in Fig. 3, Instead, the edges 5| are tearing, gouging and ripping without smoothing. Fig. '7 is diagrammatic and is enlarged considerably to show the rough saw kerf as it would appear under a microscope. Thus, according to studies I have made, the conventional saw tooth actually loosens and detaches the cellulose fibers and. splinters from a thin layer underlying the surfaceof the kerf. This pulling and tearing of the fibers makes rupture lines 52 which, when the saw approaches the thin edge of a cut, break off and actually cause the edges of the board to fracture, crack and give way. As shown in Fig. 8, on the other hand, the planing action of the divergent edges 48 on the smooth sawing tooth, shaves and dresses the surfaces of the kerf and minimizes the rupture lines 52. Further, the planing action of the edges 48 serves to shave off rather than to tear and pull the minute fibers or splinters which are present in the soft board 49'. The overall kerf width, however, is the same in both Figs. '7 and 3 since the effective tooth widths are identical.

Turning now to Fig. 5, I have shown a soft cellulose fiber insulating board 35 in the process of being resawed or split edgewise and at a taper by the saw blade Because the aforementioned datum plane and the saw work plane l8 are perpendicular, one to another, whereas the work bed plane and the plane of the work feed tunnel and the board also are perpendicular, one to another, the angle 53 of Fig. 5 is equal to the acute angle which is shown in Fig. 1 between the datum plane and work bed plane. This small acute angle produces the desired taper in the board 35 as it is split and the structure bottoming the same is an important part of my invention. Fig. 6 likewise has been enlarged somewhat and the board has been removed to reveal the opening 54 through which the saw blade I! passes as it travels down below the flat shoes 36. This opening is bounded by a fork which is an extensionof the work bed 2| and by the two lower guides 51 which are conventional in a resaw machine. Thus, Fig. 6 serves to illustrate one of the important differences between my invention and practices in attempting to split or resaw an insulating board. For example, Fig. 7 illustrates how the conventional saw tooth breaks off and tears out rather large pieces and chunks ofthe board 55; These pieces and chunks pile up and accumulate in the opening 54 and soon cause the saw blade I! to run hard. After a period of time, enough friction is created adjacent the clogged opening 54 to cause the material from the board to burst into flame. vThe danger of fire is even more enhanced if the binder material is flammable. With the tooth of Fig. 8,the pressure shoes 36, and the spray type dispenserpreviously mentioned, however, the sawdust parti: cles 56 are somewhat thinner and fiakier than those created with the conventional saw tooth. Further, since the board is not brokenor chipped in the kerf and along the thin edges, no large diameter chunks are produced to clog the opening 54. Additionally, the flaky shaving particles 56 are coated with the liquid which has been carried onthe blade I1 and which originated with the spray type dispenser 38. Thus, with my machine, the opening 54 does not clog up, no fire hazard is presented, and that binder which is released from'the board immediately is wiped away by the sawdust.

, In use, the bandsaw machine of Fig. l is started up and the spray type dispenser 38 is turned on. Thereafter, the insulating boards 35 are fed to the rectangular feed tunnel which is defined by the power driven feed rolls 25, the side fences 21, the horizontal top guide 28, and the workbed 2|. As a board is moved against the saw blade H, the flat pressure shoes 36 grip the side faces thereof, compress the board, and hold the cut pieces against the sides of the saw blade, firstly, to help produce the desired shaving'and planing action with the divergent edges 48, and, secondly, to keep the thin edges of the board from crumbling. Further, if the boards 35 are made with a binder such as a low melting point bituminous binder, the heat of the sawing action tends to cause the binder to exude.

However, because the spray type dispenser 38 has coated the saw faces with a liquid, little, if any, of the binder will stick to either the blade or the teeth. Instead, the liquid and the sawdust will act asvehicles or carriers to scrape away 1 1 and wipe ofi the-binder. as isillustrated diagram.- mati'celly in Fig: 8.

In summary, my invention: relates. toinsulatin boardv of the type:- which. is formed. inthin rec.- tangular sheets=of more. orrlessuniform thickness front a fibrous material and abitumen. or. other binder. Because of the factors heretofore explained; this method. is of outstanding. usefulness when the-thickness of the-board: doesnot. exceed one half inch. Inthis latter case..the tensile and cohesive-strength of the board is-so. limitedthat conventional methods and machines. cannot split. theboard withoutcracking off large pieces and. without starting: a. fire. With. my improved machine; howeven. these boardamay be resawed or split edgewise; with no. cracking or danger. of fire. Further, the. plane. of the,- sawkerf will be relatedto the planes ofthe rectangular sizesof theboard andit wilLbe inclined. at a. smallacute angle thereto. (see Fig. 5) taproducetwo. tapered two tapered pieceshaving. a butt. approximately three-eighths. inch thick. and. a shank end. approximately 0ne-.-eig-hth.inch. thick. The, length and widthot thetapered; piece, .of course, areunaffected. Given. such. a. board; my method. in.-

cludes. the provision of a1 continuous saw. blade having. teeth. withdivergent edges. Further... a. plurality: of fence. and guide means areprovided onthe. feed. side of.- theblade and beside the blade. for holding. and. guidingv the top,. bottom,-. and sides of. each sheet-asit; appmachestheblade and the-bottom andsides .as.the board. actually, isbeing. sawed. Further. the sideaarepressed and held. together. as, theypass. over. the saw blade.- Still. further,. a constant. velocity feedmechanism is providedto. feedeachboard pastthe fence and guidemeans. and to thesaw. blade. To produce the. tapered pieces. the feed-.mechanism-v and the. fence and. guide means. are. inclined at an. acute angle. or tilt. to. the. saw blade. as. previously explained. Sequentially,,the stepsof'my invention include coating or wetting both surfaces of the saw blade with a liquid so that binder which is caused. to exude by the heat of. the sawing actionwillbe wiped away by the sawdust. Contlnuing, a plurality of therect'angul'ar boards are fed; edgewise; one after the other, to the feed mechanism and saw blade in a constant stream and at a constant velocity with theend of each board in abutment with the following boardi finally, the-cut tapered pieces are heldtogether with a light compressive: pressure until the are well past. the: gullet' line: of. the; saw' teeth so. the planningaction of teeth: is enhanced and splitting; crumbling and cracking are; prevented;

Withthebandsaw machineeof. myinvention, on

These. areas guides... fences andpower driven feed. rolls; I! mounted upon the work bed and: are aligned inspaced pairs to bound, in outlineapl'ane'vmm feed tunnel of thesame height and thickneoaz-fl the boards which are.- to; be sawed. The. work feed. tunnel is inclined at an angle tothe. datum. plane. and-to theplane of thesaw Furthen,,tho tunnel. terminates adjacent, the novel pressure shoes. Finally, the bandsawmachine isprovided. with a. dispensermeans. which sprays an! spreads-aliquidover both faces of: the saw; bladl as the latter passes through the return planm cumulatively, these improvements provider a machine with. which insulatingfboardcan hare.- sawed or split edgewisewithout, chipping, cracking, crumblingor. catching on fire.

I- claim:

1.. A bandsaw. machine for splitting a thinxshoot ofsoftcellulose fiber board-into two tapered pieoem whichmromore thin than but.of. the same length and width; as the original-- board; said; machinv. comprising, a frame member operatively cam!- ing a power. drivenbandsa-w blade having; herb formingv and kerf planing teeth and; having; a horizontal fiat surface,- defining adatum' plane; a work bed adjustably mounted upon said tram: andhavinga fiat area defining aworkplanegsaid work. plane and datum planebeing; inclined at. am acuteangle .to one another; a. pair ofspringqbl'aooda and parallel mounted flatshoos positioned; one: on eachside of said. saw bladeto-hold the-mm pieces of boardtogether as they passoverp'the blade, and. a spray type dispenser means; carried by said frame adjacent said blade for; bathing: both facesof the latter with liquid.

2'. A- bandsaw maohinefonj azthim sheet of soft cellulose fiber board into two: tapered pieces-which are more thin thangbut'zof the some length and width as;.the-original-.board;,said'.ma' chine comprising: a frame member operativelr carrying a power drivenbandsaw blade having ker-fi forming and kerf planing; teeth: and'havingr a. horizontal. fiat surfacedefining a; datum plane, a. work bed adjustablymounted: upon; said frame and'having a fiat'areadefining awork-plane.. said! work plane. and. datum plane being inclined atan acuteangletoone another-,a pair of. springbiased. andparallel mounted flat shoespositioneds one on: eachside of said-save blade to-hold the-cutpicces: of board. together as. they; pass; oven the. blade, the. areas of. said. fiatshoesalignedwith: the: kerf formingand kerf planing; teeth; tapering". away from theremainder oi the; opposed faces of? said. flat. shoes. to. inhibit localized; pressure generated. at. the. cutting and planing. ImB'Of. said. teeth-..

3.v Abandsaw machine for splitting athin'sheet. of" soft cellulose, fiber. board, into two tapered. pieces which are more thin. than, but. of 'thesame. length and width as. the. original board. said machine comprising: aframemember. operatively C r i g. a. power driven. bandsaw blade, having kerf forming. and. kerf. planing teeth and having. a horizontal flat surfacedefining a datumplane. a workbed. adj ustabLv. mounted. upon said frameandhaving a flat-area defining, a workplane, said: work plane and datum plane being, inclinedat anacute angle to one another, a. pair of spring biased and parallel mounted fiat shoes positioned. one: on. each side of said saw blade? to-held. the cut. pieces. ofboard together as; they pass over: the blade.

R. FERRARI.

(References oni'ollowing page References Cited in the file of this patent Number UNITED STATES PATENTS Name Date Aylesbury Oct. 10, 1882 Van Severen Dec. 22, 1891 Thom Sept. 6, 1892 Pake Apr. 18, 1893 McWilliams Mar. 9, 1909 Hunt Aug. 7, 1923 Shaw Mar. 22. 1932 Number Number 10 17,137

Name Date Burton Aug. 9, 1932 Hutchings May 22, 1934 Hutchings Oct. 9, 1934 Ferrari et a1 Feb. 23, 1937 Litty Dec. 15, 1942 FOREIGN PATENTS Country Date Great Britain Sept. 13, 1895

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